Generally, a floor heating system is provided with metallic pipes embedded in a floor structure for circulating heat medium liquid theretrhough, and is arranged to raise a floor surface temperature by means of circulation of the heat medium in its circuit, such as hot water heated to a desired temperature. Such pipes made of a metal are covered with a flowable material, such as concrete or mortar so as to ensure a durability of pipes against a load or impact imposed on the floor, and are embedded in the floor structure by setting or cure of the floor substrate material or floor base material. Further, one type of floor heating system is proposed in Japanese Utility-Model Laid-Open Publication No.63-184834 (Japanese Utility-Model Application No.62-73917 filed by the present inventor) wherein hot water pipes made of elastic material are embedded within a floor substrate material. This type of floor heating system comprises a sheet, such as a heat insulation sheet or a waterproofing sheet provided on a floor slab, e.g., a concrete slab, and elastic pipes for circulating hot water, i,e., heat medium liquid. The elastic pipes are arranged on the aforementioned sheet and a floor self-leveling material is deposited and extended on the sheet and pipes.
In such a conventional floor heating system, however, a buoyancy acts on the floor heating pipes so as to lift or unseat the pipes or cause a deviation of the pipe positions, and therefore, this results in difficulties of construction work for the floor structure. Thus, overwork and complicated steps are required in a construction work, and the thickness of the self-leveling material has to be unnecessarily increased. Especially, since an increment of the thickness of self-leveling material limits an effectively usable room volume or space in a building, any improvement of construction method allowing a reduction of the thickness of self-leveling material has been desired.
Further, a surface of floor structure made in accordance with a conventional construction method may present an unacceptable irregularity or deviation of a temperature distribution owing to an uneven installation of the embedded floor heating pipes. Therefore, an improvement of construction method for relatively easily effecting uniformity in a temperature distribution has been desired.
Still further, a concrete surface or the like, on which floor heating pipes are to be installed, practically has a slight inclination or irregularity. The floor heating pipes on such an inclination or irregularity may present vertical ups and downs, offsetting or slight twist, and for that reason, it is difficult to ensure a uniform covering depth of the self-leveling material covering the pipes. Such an unevenness of the covering depth results in the aforementioned irregularity or deviation of a temperature distribution, and further, it leads to development of cracking or crazing on a floor surface in relation to the temperature variation of the floor structure.
For overcoming those disadvantages, it is an object of the present invention to provide a construction method for installing a floor heating system which can improve the efficiency of construction work and which can reduce the thickness of self-leveling material, and further, which can ensure a uniformity of temperature distribution of the floor surface and prevent cracks or crazes from being developed.